Indicates if sidebar has keyboard focus. Read Only.

<div class="definition">
    Boolean, default = false
</div>

You can navigate sidebar with keyboard using arrow keys. You can expand and collapse nodes with enter or right/left arrow keys, but it will only
work if sidebar has focus.
<div style="height: 10px"></div>

If you define sidebar in the following way:
<textarea class="javascript">
let sidebar = new w2sidebar({
    name : 'sidebar',
    nodes: [
        { id: 'id-1', text: 'Level 1' },
        { id: 'id-2', text: 'Level 2' },
        { id: 'id-3', text: 'Level 3' }
    ]
});
</textarea>

You can find if sidebar has focus by:
<textarea class="javascript">
console.log(w2ui.sidebar.hasFocus);
</textarea>